The present invention claims priority to priority document no.2001-153326 filed in Japan on May 23, 2001, and incorporated by reference herein.
1. Field of the Invention
The present invention relates to a manufacturing method for a semiconductor apparatus, and in detail, the present invention particularly relates to such a manufacturing method for a semiconductor apparatus, wherein a micro wiring pattern is formed.
2. Description of the Related Art
In recent years, the miniaturization of a wiring pattern has been quickly advanced in order to improve the degree of integration and the property of an LSI. The techniques for miniaturizing a gate length in order to improve the property of a transistor and for opening a contact hole smaller than that of a conventional contact hole in order to improve the degree of integration have been strongly requested. It is well known that a limit resolution (R) in an optical lithography process to determine the minimum size of the LSI is represented by the following equation (1):
R=kxc3x97xcex/NAxe2x80x83xe2x80x83(1)
In this case, xcex is a wave-length of a light source, NA is the numerical aperture in a projection lens, and k is a constant having a value of about 0.5.
That is, in order to attain the lithography process having a resolution higher than that of the conventional one, it is desirable to select a light source having a shorter wave-length. Because of this reason, a photolithography machine, which uses a krypton fluorine (KrF) excimer laser having a wave-length of 248 nm as a light source, is used in a field of manufacturing an high technology device. However, NA of a current exposing apparatus is 0.68 at its maximum. Thus, even the latest KrF excimer laser photolithography machine has only a resolution of about 0.18 xcexcm. However, the resolution derived from the equation (1) is applied to a banded pattern typically referred to as a line and space. Then, the resolution of the contact hole pattern has a limit of about 0.22 xcexcm.
On the other hand, a technique for opening a micro contact hole having a diameter of 0.15 xcexcm is requested in a device of 0.13 xcexcm generation. This is the size that can not be easily attained even by using an argon fluorine (ArF) excimer laser photolithography machine, which is expected as a next generation photolithography machine using a light source having a wave length of 193 nm.
As one method of solving this problem, a technique for carrying out an etching process so as to give a taper to a side wall of a hole 112 formed on a film 111 to be processed by using a resist mask 121 is known and thereby finishing it to a desired hole diameter at a bottom 112b of the hole 112, as shown in FIG. 3.
However, as shown in FIG. 4, in the above-mentioned conventional method, even if a desired hole diameter (a hole diameter on design) Db is obtained at the bottom 112b of the hole 112, a diameter Dt at an upper end (aperture) 112t of the hole 112 becomes greater than the desired size (a size on the design). This results in a problem that a sufficient matching margin can not be obtained at a later lithography process. For example, this has a problem that a distance d from a wiring 13I placed adjacently to the hole 112 is made narrower.
The present invention is a manufacturing method for a semiconductor apparatus proposed in order to solve the above-mentioned problems.
The manufacturing method of a semiconductor apparatus of the present invention includes the steps of: forming a mask material film made of organic insulation film on a film to be processed; forming a tapered opening pattern or aperture pattern, in which a bottom is narrower than an open side on the mask material film; and etching the film to be processed using the mask material film as a mask.
In accordance with the manufacturing method of the semiconductor apparatus, after the mask material film is formed on the film to be processed, the tapered aperture pattern that is narrower at the bottom side than at the aperture side is formed on the film to be processed, and thereby it is possible to able to form the bottom of the aperture pattern at the desired micro dimension exceeding the limit of the lithography technology. The film to be processed is then etched by applying thus-processed mask material film as a mask, thereby, the film to be processed can be vertically etched to the micro dimension exceeding the limit of the lithography technology.
As mentioned above, according to the manufacturing method of the semiconductor apparatus of the present invention, after the mask material film is formed on the film to be processed, the tapered aperture pattern in which the bottom is narrower than the aperture side is formed on this mask material film. Thus, the bottom of the aperture pattern can be formed at the desirable micro dimension exceeding the limit of the lithography technique. The thus-processed mask material film is used as the mask, and the film to be processed is etched. Hence, the film to be processed can be vertically etched to the micro dimension exceeding the limit of the lithography technique. Therefore, since the film to be processed can be processed under the excellently controlling performance with regard to the size, the matching margin is never decreased differently from the conventional direct taper etching method.